From: Christian Eggers <ceggers@arri.de>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Oleksij Rempel <linux@rempel-privat.de>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>,
<linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
NXP Linux Team <linux-imx@nxp.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
<linux-arm-kernel@lists.infradead.org>,
<linux-i2c@vger.kernel.org>
Subject: Re: [PATCH 1/3] i2c: imx: Fix reset of I2SR_IAL flag
Date: Thu, 17 Sep 2020 16:13:50 +0200 [thread overview]
Message-ID: <16013235.tl8pWZfNaG@n95hx1g2> (raw)
In-Reply-To: <20200917140235.igfq2hq63f4qqhrr@pengutronix.de>
Hello Uwe,
On Thursday, 17 September 2020, 16:02:35 CEST, Uwe Kleine-König wrote:
> Hello,
>
> On Thu, Sep 17, 2020 at 02:20:27PM +0200, Christian Eggers wrote:
> ...
> > /* check for arbitration lost */
> > if (temp & I2SR_IAL) {
> > temp &= ~I2SR_IAL;
> > + temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL);
> > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> > return -EAGAIN;
> ...
> This looks strange. First the flag is cleared and then it is (in some
> cases) set again.
i.MX controllers require writing a 0 to clear these bits. Vybrid controllers
need writing a 1 for the same.
> If I2SR_IIF is set in temp you ack this irq without handling it. (Which
> might happen if atomic is set and irqs are off?!)
This patch is only about using the correct processor specific value for
acknowledging an IRQ... But I think that returning EAGAIN (which aborts the
transfer) should be handling enough. At the next transfer, the controller will
be set back to master mode.
> I see this idiom is used in a few more places in the driver already, I
> didn't check but these might have the same problem maybe?
Best regards
Christian
next prev parent reply other threads:[~2020-09-17 14:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 12:20 [PATCH 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-09-17 12:20 ` [PATCH 1/3] i2c: imx: Fix reset of I2SR_IAL flag Christian Eggers
2020-09-17 14:02 ` Uwe Kleine-König
2020-09-17 14:13 ` Christian Eggers [this message]
2020-09-25 8:11 ` Uwe Kleine-König
2020-10-02 8:01 ` Christian Eggers
2020-10-02 10:21 ` Uwe Kleine-König
2020-09-17 12:20 ` [PATCH 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-09-17 12:20 ` [PATCH 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Christian Eggers
2020-09-25 7:03 ` [PATCH 0/3] i2c: imx: Fix handling of arbitration loss Oleksij Rempel
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